Editors' note: Elon Musk has concluded his update on SpaceX's Mars plans. He announced lots of new details about the Mars rocket (aka BFR), promoted the possibility of a lunar base and suggested BFR could fly anywhere on Earth in less than an hour. As for the actual plans to colonize Mars, Musk offered a nice rendering of what a city might look like, but no further details, which means all the questions raised in our story earlier on Thursday still stand. That story is below.

Musk's preliminary outline, unveiled in Mexico last year, offered few specifics on what life will actually be like on Mars. It didn't address how colonists will avoid radiation poisoning or how to supply them with food and clean water.

Musk did make a vague reference to work being done on a potential nuclear-powered sewer and sanitation system for Mars. But his general attitude seems to be that he'll provide rockets and spaceships and everything else will be sorted out along the way.

"We're going to have to get down to the nitty-gritty," Kate Greene, a writer and former laser physicist, told a crowd of space enthusiasts in Santa Fe, New Mexico, in July.

"Day-to-day living on the Mars mission," Greene said, "we were thinking about toilet paper. We were thinking about toilets working well. We were thinking about who's doing the dishes."

Kate Greene in a simulated space suit at HI-SEAS in 2013.

HI-SEAS/Sian Proctor

SFI is an independent research center that studies "complexity science," and the Interplanetary Project borrows from the Star Trek ethos. That is, it makes the assumption that uniting people around a big goal like becoming a multiplanetary species, as Musk puts it, could also help us confront some of our big challenges here on Earth, like tackling climate change and fighting disease.

"The argument is that we're going to solve our problems here by trying to get elsewhere," said Dario Robleto, an artist-in-residence at the SETI Institute.

Santa Fe Institute President David Krakauer expanded on that connection at a gathering of panelists and journalists following this summer's event. "We are bad at predicting how areas of inquiry connect, and the one thing that we do know historically is that very ambitious questions often connect to toilet paper," he said.

It's not that Mars fans are obsessed with bathroom tissue, although it sure came up a lot. To explain, Krakauer cited the example of Galileo, whose observations of the solar system led to a scientific revolution in areas beyond just astronomy. Those advances still affect our everyday lives centuries later, including the engineering knowledge required to mass produce and distribute things like, yes, toilet paper. (It was first introduced by Joseph Gayetty in 1857, thank you very much.)

At SFI's Sante Fe event, award-winning astrophysicist Sandra Faber didn't hold back in her evaluation of what drives Musk and other billionaires like Amazon founder Jeff Bezos in the new space race.

"Testosterone," she said, receiving a round of laughter and applause from the crowd.

Famed sci-fi author Neal Stephenson agreed. "It's absolutely testosterone," he said. "And then there's just the strange phenomenon of certain people making a lot of money and having the resources to apply against these kinds of projects."

Neal Stephenson (left), Sandra Faber and David Krakauer on stage at the Lensic Theater in Santa Fe, New Mexico.

And even if Musk, the luminaries gathered by SFI and the rest of humanity agree that Mars is a goal worth pursuing, there are still an overwhelming number of questions.

For starters, building an ecosystem from scratch on Mars that can provide food, water and oxygen to support a colony is no small task. Krakauer points out that attempts to create independent ecosystems have typically failed.

"We can't create now, with everything we know scientifically, an autonomous ecosystem in lab conditions on the planet Earth with more than five species," he said.

There there's the question of who should go.

Stephenson suggests that in the case of some existential threat to Earth's population, which is one motivation Musk cites for his Mars plan, we would need a colonist selection scheme "that leads to the least warfare and murder on Earth." That would likely come together through a series of political compromises.

Greene points out that women consume fewer calories on average, so an all-female crew might make the most sense on spaceships where weight taken up by food stores is a consideration.

Jonathan Nolan, creator of the HBO series "Westworld" and co-writer of 2014's "Interstellar," raised the notion that perhaps humans may not be our best option.

Jonathan Nolan shared his thoughts on colonizing the universe from the set of "Westworld."

Michael Ferrara/CNET

"So much of what we have to do to explore space would be compromised by our own human frailty," he said in a pre-recorded video. "In any given spaceship, we are the most vulnerable component … We may well want to leave most of the exploring up to our creations."

"Maybe AI won't be that terrible," Nolan said. "Maybe it will be wonderful."

Seeing red in the future

We'll see if Musk addresses any of the more practical Mars considerations on Friday. Perhaps he has a plan to create a crew of Martian colonist cyborgs who communicate using a brain-computer interface like what one of his companies, Neuralink, is developing.